The present invention relates to a plant maintenance control system and in particular to the exploitation of a computer in such context as a technological tool to enable strict and enforceable controls over the maintenance expenses involved in a complicated and expensive plant such as a chemical plant.
It has been known to establish certain controls over maintenance expenses in complicated plants, but generally this has been effectuated by means of a primarily batch-oriented system. In particular, it has been the experience of the inventor of the present system to work in a chemical plant with a batch-oriented system primarily designed to monitor and report departmental labor utilization as an upper management control. However, with such a system, relatively little provision is made to monitor material utilization and outside repair expenses. The relative importance of the aforementioned elements of cost may be broken down as follows: labor wages generally constitute about 42% of the total cost, whereas, maintenance materials constitute about 46%, and outside repairs 12%.
From the above percentages, it will be understood that the prior system or systems have lacked the facility for monitoring the very significant portion, that is, the approximately 58% of total costs, and, accordingly, have been deficient for these reasons. In addition, a system that is batch-oriented has severe drawbacks, particularly in that a significant time must elapse before results can be achieved and it is incapable of providing immediately the important information affecting decision-making with respect to the utilization of certain items. For example, one often wants to know immediately the history of the maintenance performed on certain equipment so that decisions can be made as to the future use of components that appear to be in constant need of maintenance.
Accordingly, the present invention is directed to a fully integrated data base system; that is, one that uniquely establishes, organizes and arranges the individual physical data bases, and further, uniquely provides logical interrelationships that produce an efficient information system given the variety of parameters involved.
Inasmuch as the system of the present invention is envisioned for use with IMS (Information Management System), a fully integrated system offered by IBM, reference can be made by way of background material to IBM disclosure materials on this subject, such as Access Method Services Manual; IMS/VS Version 1 Utilities Reference Manual; IMS/VS Version 1 Message Format Service Users Guide; BTSII/Batch Terminal Simulator II Program Description and Operations Manual; IMS/VS Version 1 Application Programming Reference Manual; and IMS/VS Version 1 System/Application Design Guide.
The terms used in the present specification will, for the most part, correspond with terms used in that IBM data base system. As is generally understood, certain standard terminology already accepted in the computer industry will also be utilized herein; as for example, "bits", which are grouped into .-+.bytes" or characters, characters being grouped into fields, etc. However, in accordance with the general scheme of IMS, which is based on the development of a special data language known as DL/I, fields are grouped into segments and segments are the nodes of tree structures. By "tree structure" is meant a well-known structure in accordance with a so-called hierarchical approach, as can be appreciated by reference to a standard work, such as "Database" by David Kroenke (published 1978 by Science Research Associates, Inc.), particularly to page 15 et seq.; 210 et seq., where a variety of definitions are given. A particular tree structure is referred to as a data base record and a complete data base is composed of a plurality of data base records, which may be occurrences of the same record type or of several record types.
Fundamental to an understanding of the present invention are the basic principles of so-called data base processing. One of these principles is integration of data by which is meant that the data is processed as an integrated whole. Also, all of the data is compatible since the "files" have been created by a data base processing system, that is to say, a common system. Another important feature of data base processing is the elimination or reduction of data duplication. In a conventional file processing system, data is likely to be recorded in several different files, whereas in a data base system, it need only be recorded once. Such elimination of duplication saves file space and can reduce processing requirements. Moreover, elimination of duplication can result in data integrity, whereas in conventional arrangements, it's possible to change the data in one place or file, but not in another, such that data items may differ and result in conflicting reports issuing as a result of the system's operation.
It should be noted that the DL/I model utilized in the Information Management System marketed by IBM provides for two types of data base records: physical data base records (PDBR) and logical data base records (LDBR). A PDBR is a hierarchy of segments that physically exist. One example of this can be appreciated by reference to page 23 of the aforenoted work by Kroenke entitled, "Database". An LDBR is a logical, or symbolic, hierarchy of segments. An LDBR differs from a PDBR in either or both of two ways. An LDBR may be sensitive to a subset of the segments in a PDBR. The second potential difference between an LDBR and a PDBR is that the LDBR may logically connect two or more PDBR's.
It is also important to note that IMS includes its own internal data communications processor which performs the needed communications between the user and the data base, it being understood that generally speaking, there are three components involved in data base processing: the user or his application programs, the system support software, and the data base itself. This can be appreciated by the graphical presentation shown on page 9 of the Kroenke work. By the term "user", one is not referring to a particular individual but to a group of individuals whose primary orientation to the data base is use. These users can interact with so-called application programs which in turn use the data base system. When users interact directly, they use English-like statements known as query language.
A primary object of the present invention is to design the total data base in an optimal way such that complete control over plant maintenance expenses can be established, whereby total costs will be minimized. This is accomplished through a unique arrangement of relationships among the individual data bases which together constitute the total storehouse of data on the significant parameters involved in plant maintenance. By reason of these relationships, flexible and timely access to the data can be gained so as to yield the requisite information by which the necessary control can be realized. This particular object and its fulfillment will become clear as the description proceeds.
The primary goal of the maintenance function--keeping the physical plant in a safe, economical operating condition--depends to great measure on the timely availability of detailed information of:
(a) current demand for services, (b) relative priority of individual jobs, (c) identification of required materials, (d) availability of materials, and (e) craft requirements along with probable duration.
As maintenance functions increase in size and complexity from small to large, it becomes increasingly more difficult and expensive to gather, collate, analyze, and distribute the required information. Additionally, the effects of an increasing rate of technological change tends to negate the benefits of prior personal experience.
This system of the invention was designed to be modular in its application but with provision to inter-relate the various modules in a machine logic which replicates the traditional inquiry without the redundance of manual files or stand-alone systems. The system obtains its daily information from hourly personnel time sheets, purchase requisitions, and storeroom withdrawal authorizations. This information, along with a chart of accounts and cost center, is required to satisfy internal cost accounting requirements. By capturing this information at its lowest level of detail, it is then convenient for cost trends to be analyzed to any degree of detail required.
Individual machines or groups of machinery which perform a discrete function are identified and cross referenced to both specific asset numbers and plant layout drawings. These machinery groupings are in turn cross referenced to the cost center definitions and product cost sheets. The system incorporates a work order system which is inter-related to the other modules and provides the current status of work in process and preliminary planning. The data provided by vendors relative to performance characteristics and spare parts requirements for specific pieces of machinery are inter-related to the asset files and the plant layout drawings. The spares requirements are in turn interrelated to the spares inventory modules which, via stores stock numbers, are inter-related to a purchasing system.
Other major objects of the system of the present invention are to provide on-line editing and updating with respect to the activity or maintenance request orders.
Another object is to provide on-line retrieval of the history of maintenance request orders.
A further object is to enable the maintenance analyst or foreman involved in maintenance to monitor and control cost rather than just report expenses. In other words, the present invention gives maintenance control a "before the fact" visibility and reporting rather than being just an "after the fact" system.
Still another object is to provide greatly increased accuracy in the cost data obtainable.
The system of the present invention has been applied in a complicated plant as noted previously; that is to say, in a chemical plant which employs on the order of one thousand or more people and involves invested capital of hundreds of millions of dollars. In such environment, it is of crucial importance that a maintenance control system, that is, a system which is designed to monitor and control plant maintenance expenses, be a thoroughly efficient one. In actual application, the system of this invention has effected over-all savings of the order of one million dollars per year. This highly advantageous cost savings has been accomplished because of the aforenoted detail control which the system provides over maintenance materials and outside repairs that constitute major components in the total cost picture. In other words, while formerly only wages were efficiently monitored as an upper management control, the present invention goes beyond that and enables up-to-the-minute monitoring of materials and outside repairs, as well as of wages attributable to plant maintenance activities.
In fulfillment of the aforenoted objects, a primary feature of the present invention resides in the unique arrangement by which logical relationships are established among the plurality of individual data bases that are provided; in other words, broadly stated, the primary feature fully exploits the capability of known data systems so as to enable an integrated data collection; further, to permit display and "print out" of the required information that will provide control over the lowest level of detail on maintenance requests and the like. For example, it permits pin-pointing the fact that certain cost centers may not be adhering to their budgets or that certain equipment, as indicated by the information from the SUBMOD data base, is not performing satisfactorily. The parts, for example, are wearing out too quickly; specifically, the maintenance department can look to see if emergency repairs on pump seals, as an example, are occurring too frequently, and can check on the total cost of this.
It should be noted that in the chemical plant in which an embodiment of the present invention has been implemented, the number of maintenance requests per day that are involved may average one hundred and the number of transactions per maintenance request may average as much as eighty. Although in the implemented system not all cost centers will accept maintenance charges, there are 270 separate cost centers that do so and the number of SUBMODS is of the order of 6500, while the maintenance projects average 250. By the term "SUBMOD" is meant a functional group of components, such as a pump and the motor which drives the pump, which group is assigned a service number.
The maintenance control system of the present invention has been developed in several stages because of its complexity. Consequently, the primary feature of the present invention alluded to above resides in the initial phase or the "maintenance request phase" of the system. Thus, emphasis will be placed on the fundamental logical pointer relationships among the maintenance request data base, the maintenance project data base, the cost center data base, and the so-called SUBMOD data base, these four data bases forming the total data base complex of the initial phase. Subsequently, as the initial phase "proved out", further data bases, numbering twelve in all, were added to the system and these will be explained as the description proceeds. In a similar way, the added data bases have also been completely integrated, with each other and with those of the initial phase, by means of logical pointer relationships so that a whole variety of access points are available to one accessing the data base complex. Again, this will be fully explained in the later parts of the specification.
Other and further objects, advantages and features of the present invention will be understood by reference to the following specification in conjunction with the annexed drawing, wherein like parts have been given like numbers.